| 摘要 |
PROBLEM TO BE SOLVED: To improve a chip discharging property, without impairing bottom blade hardness.SOLUTION: At a tip end portion of an end mill body 1, a gash 6, which is equipped with a first gash portion 10 extending from a tip end of a chip discharging groove to an inner peripheral side, and a second gash portion 11 extending from the first gash portion 10 to the further inner peripheral side, is formed. A bottom blade is formed at least at a tip end side ridge portion of a wall surface 11A turned in an end mill rotating direction T of the second gash portion 11, and a wall surface 10A turned in an end mill rotating direction T of the first gash portion 10 extends to the opposite side to the end mill rotating direction T toward an outer peripheral side, with respect to the wall surface 11A.SELECTED DRAWING: Figure 4 |
